WO2010098036A1 - Dispositif électroluminescent et élément électroluminescent - Google Patents

Dispositif électroluminescent et élément électroluminescent Download PDF

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Publication number
WO2010098036A1
WO2010098036A1 PCT/JP2010/000948 JP2010000948W WO2010098036A1 WO 2010098036 A1 WO2010098036 A1 WO 2010098036A1 JP 2010000948 W JP2010000948 W JP 2010000948W WO 2010098036 A1 WO2010098036 A1 WO 2010098036A1
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WO
WIPO (PCT)
Prior art keywords
light
light guide
scattering
emitting device
led
Prior art date
Application number
PCT/JP2010/000948
Other languages
English (en)
Japanese (ja)
Inventor
望月恵一
Original Assignee
日東光学株式会社
小池康博
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 日東光学株式会社, 小池康博 filed Critical 日東光学株式会社
Priority to US13/202,806 priority Critical patent/US8727591B2/en
Publication of WO2010098036A1 publication Critical patent/WO2010098036A1/fr

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0005—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being of the fibre type
    • G02B6/001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being of the fibre type the light being emitted along at least a portion of the lateral surface of the fibre
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/024—Details of scanning heads ; Means for illuminating the original
    • H04N1/028—Details of scanning heads ; Means for illuminating the original for picture information pick-up
    • H04N1/02815—Means for illuminating the original, not specific to a particular type of pick-up head
    • H04N1/0282—Using a single or a few point light sources, e.g. a laser diode
    • H04N1/02835—Using a single or a few point light sources, e.g. a laser diode in combination with a light guide, e.g. optical fibre, glass plate
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/024—Details of scanning heads ; Means for illuminating the original
    • H04N1/028—Details of scanning heads ; Means for illuminating the original for picture information pick-up
    • H04N1/02815—Means for illuminating the original, not specific to a particular type of pick-up head
    • H04N1/02885—Means for compensating spatially uneven illumination, e.g. an aperture arrangement
    • H04N1/0289—Light diffusing elements, e.g. plates or filters
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/0038—Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0058—Means for improving the coupling-out of light from the light guide varying in density, size, shape or depth along the light guide
    • G02B6/0061—Means for improving the coupling-out of light from the light guide varying in density, size, shape or depth along the light guide to provide homogeneous light output intensity
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
    • H04N2201/0077—Types of the still picture apparatus
    • H04N2201/0081—Image reader

Definitions

  • the present invention relates to a light emitting device and an optical element.
  • LEDs Light Emitting Diodes
  • the scanning illuminator has an optical element that defines an entrance surface and opposing back and exit surfaces.
  • the exit surface is substantially perpendicular to the entrance surface
  • the back surface includes a reflective element including a plurality of prisms that redirect light received from the entrance surface toward the front surface.
  • the illuminator then has a particulate material disposed between the reflective element and the front surface to diffuse the incident light.
  • the illuminator has at least one LED light source disposed adjacent to the incident surface (see Patent Document 2).
  • the lighting device described in Patent Document 1 requires many LEDs.
  • the brightness of the light-irradiated portion of each LED is different from that of the light-irradiated portion, and a member that strongly scatters the emitted light is required for use as illumination for scanning. Therefore, it is difficult to make the emitted light brighter than using many LEDs.
  • the illuminator described in Patent Document 2 tends to deteriorate the light efficiency due to the light penetrating the reflecting element, and tends to cause a strong and weak distribution in the emitted light.
  • an object of the present invention is to provide a light emitting device and an optical element that can increase the efficiency of light and reduce manufacturing difficulties while suppressing the occurrence of strong and weak distribution in the emitted light.
  • a light-emitting device of the present invention changes the direction of light incident from a longitudinal end of a light guide unit, a light source that makes light incident on the light guide unit, a light source that enters the light guide unit.
  • a light emitting device that emits light whose direction has been changed from an emission surface disposed so as to face the prism portion, and the light guide portion has a longitudinal end portion directed from the light source toward the light guide portion.
  • the light source is made to approach the parallel light by shifting from the central axis of the light guide part to the side approaching the prism part or the side away from the prism part.
  • the light is directed to the exit surface of the light guide section or the prism section.
  • the light source is disposed to be inclined with respect to the central axis of the light guide.
  • the parallel light forming body is a convex lens whose side facing the light source is swollen.
  • a reflection member that reflects light that is not directly incident on the light guide unit from the light source to enter the light guide unit is provided around the light source.
  • a light scattering light guide containing light scattering particles for multiply scattering the emitted light is provided on the exit surface side of the light guide that emits light.
  • the prism portion so as to be parallel to the exit surface.
  • an optical element of the present invention has a rod-shaped light guide part and a prism part that changes the direction of light incident from the end in the longitudinal direction of the light guide part, and faces the prism part.
  • the optical element that emits the light whose direction is changed from the emission surface arranged so as to make the light emitted from the light source toward the light guide unit closer to the parallel light at the longitudinal end of the light guide unit.
  • a light scattering light guide containing light scattering particles for multiply scattering emitted light is provided on the exit surface side.
  • the light-scattering light guide portion is formed in a rod shape, and the surface opposite to the surface facing the light guide portion has a convex curved shape in which the central portion in the short direction swells.
  • the light guide part and the light scattering light guide part may be integrated.
  • the light guide unit contains light scattering particles that scatter multiple incident light.
  • the light scattering particles are preferably translucent silicone particles having a particle size of 2 ⁇ m to 9 ⁇ m.
  • the light scattering particles contained in the light guide unit are 0 when turbidity, which is a scattering parameter corresponding to the scattering coefficient of the light guide unit, is ⁇ , and the length in the central axis direction of the light guide unit is L. It is preferable to be within the range of ⁇ L / (2 ⁇ ⁇ ) ⁇ 30.
  • the light scattering particles contained in the light scattering light guide unit are turbidity, which is a scattering parameter corresponding to the scattering coefficient of the light scattering light guide unit, ⁇ , and the light scattering light guide unit in the direction orthogonal to the exit surface.
  • T the maximum thickness
  • the present invention it is possible to provide a light emitting device and an optical element that can increase light efficiency and reduce manufacturing difficulties while suppressing the occurrence of intensity distribution in emitted light.
  • the figure which shows the incident / exit condition of the light when the LED of the light emitting device according to the embodiment of the present invention is lit, is emitted from both ends of the LED when the LED is shifted to the prism portion side and is arranged tilted
  • the figure which shows the incident / exit condition of light when the LED of the light emitting device of the first modification of the light emitting device according to the embodiment of the present invention is turned on is arranged without shifting the LED to the prism portion side and tilting
  • the figure which shows the incident / exit condition of light when the LED of the light emitting device of the first modification of the light emitting device according to the embodiment of the present invention is turned on is arranged without shifting the LED to the prism portion side and tilting
  • the figure which shows the incident / exit condition of the light when the LED of the light emitting device of the second modification of the light emitting device according to the embodiment of the present invention is turned on is arranged without shifting the LED to the emitting surface side and tilting
  • the figure which shows the incident / exit condition of the light when the LED of the light emitting device of the second modification of the light emitting device according to the embodiment of the present invention is turned on is arranged without shifting the LED to the emitting surface side and tilting
  • the figure which shows the light emission state of the 2nd modification of the light-emitting device which concerns on embodiment of this invention is a figure which shows distance from the center part of a light guide part on a horizontal axis, and shows the distribution of the brightness (light quantity) of a light guide part It is.
  • the figure which shows the light emission state of the light-emitting device of the 3rd modification of the light-emitting device which concerns on embodiment of this invention takes the distance from the center part of a light guide part on a horizontal axis, and distributes the brightness (light quantity) of a light guide part
  • FIG. The figure which shows the condition of the light incident / exit when turning on LED of the light-emitting device of the 3rd modification of the light-emitting device which concerns on embodiment of this invention, and LED of the case at the time of arrange
  • positioning LED without shifting and tilting It is a schematic diagram which shows the optical path of the light which the light radiate
  • FIG. 1 is a front view showing a configuration of a light guide 1 which is an optical element according to an embodiment of the present invention
  • FIG. 2 is a side view thereof.
  • the light guide 1 has a rod shape whose outer shape is close to a long rectangular column.
  • the light guide 1 is formed on the lower surface of the light guide 2, the light guide 2, the incident lenses 3 provided at both ends in the longitudinal direction of the light guide 2, and the light guide 2 shown in FIGS. 1 and 2. It has the prism part 4 used as a part, and the light-scattering light guide part 5 arrange
  • the light guide 2 is a resin molded body made of transparent polymethyl methacrylate (hereinafter abbreviated as “PMMA”), and has a quadrangular prism shape.
  • the incident lens 3 is also a convex lens made of PMMA and having a hyperbolic cross section. The light guide 2 and the incident lens 3 are integrally formed.
  • the incident lens 3 serving as the parallel light forming body is a convex lens that swells on the side away from the light guide portion 2, that is, on the outside.
  • the detailed configuration of the prism unit 4 is not shown, and the detailed description of the prism unit 4 will be described later.
  • the light scattering light guide 5 is a PMMA resin molded body containing spherical and translucent silicone particles (not shown) having a particle diameter of 2 ⁇ m to 9 ⁇ m as light scattering particles.
  • the length direction dimension L2 and the length direction dimension W2 of the light-scattering light guide 5 are the same as the length direction dimension L1 and the length direction dimension W1 of the light guide 2, respectively.
  • the dimension H2 is smaller than the dimension H1 of the light guide 2 in the thickness direction.
  • the upper surface of the light scattering light guide 5 swells from both ends in the short direction toward the center.
  • the shape of this bulge is the shape of a part of the side surface of the cylinder. That is, the surface is a part of a spherical surface.
  • the light guide part 2 and the light-scattering light guide part 5 are integrated by 2 material shaping
  • the light-scattering particles contained in the light-scattering light-guiding unit 5 have a turbidity that is a scattering parameter corresponding to the scattering coefficient of the light-scattering light-guiding unit 5 as ⁇ (unit: cm), and will be described later.
  • ⁇ unit: cm
  • the maximum thickness (H2) of the light-scattering light guide 5 in the direction orthogonal to T is T (unit: cm)
  • the range is 1 ⁇ T / ⁇ ⁇ 10.
  • This silicone particle is a light guide provided with a volumetric uniform scattering ability, and includes a large number of spherical particles as scattering fine particles. When light enters the light scattering light guide 5, the light is scattered by the scattering fine particles.
  • Mie scattering theory is the solution of Maxwell's electromagnetic equation for the case where spherical particles (scattering fine particles) having a refractive index different from that of the medium exist in a medium (matrix) having a uniform refractive index. .
  • the intensity distribution I ( ⁇ , ⁇ ) depending on the angle of the scattered light scattered by the scattering fine particles corresponding to the light scattering particles is expressed by the following equation (1).
  • ⁇ is a size parameter indicating the optical size of the scattering fine particles, and is an amount corresponding to the radius r of the spherical particles (scattering fine particles) normalized by the wavelength ⁇ of light in the matrix.
  • i 1 and i 2 in the formula (1) are represented by the formula (4).
  • a and b with the subscript ⁇ in the expressions (2) to (4) are expressed by the expression (5).
  • P (cos ⁇ ) with superscript 1 and subscript ⁇ is Legendre's polynomial
  • a and b with subscript ⁇ are first-order and second-order Recati-Bessel functions ⁇ * , ⁇ * (where “*” Means the subscript ⁇ ) and its derivative.
  • m is the relative refractive index of the scattering fine particles based on the matrix
  • m nscatter / nmattrix.
  • FIG. 3 is a graph showing the intensity distribution I ( ⁇ , ⁇ ) by a single true spherical particle based on the above equations (1) to (5).
  • FIG. 3 shows an angular distribution I ( ⁇ , ⁇ ) of scattered light intensity when there is a true spherical particle as a scattering fine particle at the position of the origin G and incident light is incident from below.
  • the distance from the origin G to each of the curves S1 to S3 is the scattered light intensity in each scattering angle direction.
  • Curve S1 shows the scattered light intensity when ⁇ is 1.7
  • curve S2 shows the scattered light intensity when ⁇ is 11.5
  • curve S3 shows the scattered light intensity when ⁇ is 69.2. Yes.
  • the scattered light intensity is shown on a logarithmic scale. For this reason, the portion that appears as a slight difference in intensity in FIG. 3 is actually a very large difference.
  • the larger the size parameter ⁇ (the larger the particle size of the true spherical particle when considered at a certain wavelength ⁇ ), the higher the directivity with respect to the upper side (front of the irradiation direction). It can be seen that light is highly scattered. Actually, the angle distribution I ( ⁇ , ⁇ ) of the scattered light intensity is controlled by using the radius r of the scatterer and the relative refractive index m of the medium and the scattered fine particles as parameters if the incident light wavelength ⁇ is fixed. can do.
  • the light scattering light guide 5 has a large forward scattering.
  • I ( ⁇ ) in the equation (6) is the scattering intensity of the true spherical particle having the size parameter ⁇ represented by the equation (1). Assuming that light of intensity Io enters the light scattering light guide and passes through the distance y, the intensity of the light attenuates to I due to scattering, and these relationships are expressed by the following equation (7).
  • ⁇ in the equation (7) is called turbidity and corresponds to the scattering coefficient of the medium, and is proportional to the number N of particles as in the following equation (8).
  • ⁇ s is a scattering cross section.
  • the degree of multiple scattering in the light scattering light guide can be controlled by changing the turbidity ⁇ .
  • FIG. 4 is a schematic diagram showing a side surface shape of the prism portion 4 existing about half the length from the longitudinal end portion of the light guide portion 2.
  • Trapezoidal convex portions 10, 11, and 12 are formed on the surface facing the emission surface 6 that is the upper surface of the light guide portion 2, that is, on the lower surface of the light guide portion 2.
  • sawtooth-shaped concave portions 13 and 14 are formed by adjacent convex portions 10, 11, and 12. The apex of the sawtooth is the most recessed portion of the recesses 13 and 14.
  • the convex portion 10, 11, 12 and the concave portion 13, 14 constitute the prism portion 4.
  • the shape of the prism portion 4 is symmetrical with respect to the center in the longitudinal direction of the light guide portion 2 and is symmetrical with respect to the center in the short direction.
  • the pitch P1 between the vertices of the concave portion 14 at the center of the light guide 2 is set larger than the pitch P2 between the vertices of the concave 13 at both ends of the light guide 2.
  • the convex portions 10, 11, 12 and the concave portions 13, 14 are formed at the same time when the light guide portion 2 and the incident lens 3 are integrally formed by a mold.
  • FIG. 5 is a longitudinal sectional view of a light emitting device 20 using the light guide 1.
  • an LED 21 as a light source and a mirror member 22 as a reflecting member are fixedly arranged.
  • the LED 21 is of a chip type.
  • the LED 21 is disposed closer to the prism portion 4 than the optical axis M1 of the incident lens 3 (lower side in FIG. 5). That is, the LED 21 is shifted downward with respect to the optical axis M1. As a result of this shift, the arrangement position of the LED 21 is an intermediate position between the optical axis M1 and the prism portion 4.
  • the optical axis M ⁇ b> 1 of the incident lens 3 is a line that is parallel to the prism portion 4, is also parallel to the exit surface 6, and passes through the center of the incident lens 3.
  • the LED 21 is disposed so as to be inclined by 45 ° with respect to the optical axis M1 so as to irradiate the incident lens 3 with light from the lower side to the oblique upper side in FIG. That is, the surface of the LED 21 is not perpendicular to the optical axis M1, but is tilted and tilted. As a result, the LED 21 is shifted to the prism portion 4 side with respect to the optical axis M1, and is tilted so as to face the emission surface 6 side.
  • Each mirror surface member 22 has a cup shape in which the longitudinal section in FIG. 5 draws a parabolic curve.
  • This parabola is the same when cut by any cross section including the optical axis M1.
  • the focal position of the parabola is set to be on the optical axis M1.
  • the inner surface of the cup-shaped mirror member 22 is mirror-finished so that the light from the LED 21 can be reflected.
  • the opening end portion of the cup-shaped mirror surface member 22 covers the end portion of the light guide 1, and the LED 21 is glazed so that the light from the LED 21 does not leak between the mirror surface member 22 and the light guide body 1. For this reason, most of the light from the LEDs 21 placed at both ends of the light guide 1 is incident on the light guide 1.
  • FIG. 6 shows an optical path of light emitted from both ends of the LED 21 (only the left end side is shown in the figure) when light is directly incident on the incident lens 3 from the LED 21.
  • FIG. 7 shows a case where light from the LED 21 is reflected by the mirror member 22 and is incident on the incident lens 3 and light emitted from both ends of the LED 21 (only the left end is shown in the figure). The optical path is shown.
  • An optical path indicated by a fine dotted line with an arrow is an optical path of light emitted from the lower end side of the LED 21 in FIGS. 6 and 7.
  • the light emitted from the center of the LED 21 is an intermediate optical path between them, but the illustration is omitted.
  • the optical path shown with the rough dotted line with an arrow is an optical path of the light emitted from the upper end side of LED21 in FIG. 6 and FIG.
  • the light guide unit 2 and the light scattering light guide unit 5 are separated from each other. (The same applies to FIGS. 9, 10, 11, 12, 13, and 14).
  • the LED 21 is disposed so that the center of the LED 21 is slightly below the focal position F that is the focal position of the incident lens 3 and the parabolic focus position of the mirror member 22. However, in FIG. 6 and FIG. 7, for the sake of easy understanding, the center of the LED 21 is shown at a position considerably away from both focal positions F.
  • the light emitted from the LED 21 is divergent light, but after entering the incident lens 3, it approaches parallel light by the action of the convex lens. And the light which directly injects into the incident lens 3 from LED21 is once irradiated to the output surface 6 (it becomes an upper side surface) of the light guide part 2 in FIG.
  • the light is totally reflected by the emission surface 6 and is changed in direction mainly by the prism portion 4 at the center of the light guide portion 2. Then, the light whose direction has been changed passes through the emission surface 6 in a substantially vertical direction, and further passes through the light scattering light guide 5 while being scattered, and is emitted.
  • the light shown in FIG. 6 is emitted mainly from the center of the light guide 2.
  • the emitted light from the center of the light guide is weakened and the intensity distribution of the emitted light tends to be large.
  • the emitted light from the center part is apt to be obtained. Becomes stronger and the strength distribution becomes gentler.
  • the light from the LED 21 reflected by the mirror member 22 and incident on the incident lens 3 may be light that takes the same optical path as shown in FIG. However, as shown in FIG. 7, a part of the light passes through the incident lens 3 from the mirror surface member 22 and is directly irradiated to the prism unit 4 without undergoing total reflection on the emission surface 6, and is redirected to change the emission surface. 6 passes through in a substantially vertical direction, and further passes through the light-scattering light guide 5 while being scattered. The light shown in FIG. 7 is emitted mainly from both end portions of the light guide unit 2.
  • FIG. 8 is a diagram showing the distribution of brightness (light quantity) of the light guide unit 2 as a simulation result, with the distance from the center of the light guide unit 2 being taken on the horizontal axis.
  • the simulation condition is that the light emitting surface of the LED 21 is 1 mm square, the brightness is 150 lumens / piece, the spread angle is 160 °, and the surface of the light scattering light guide 5 opposite to the surface facing the exit surface 6. This is a condition for displaying the brightness at a position 10 mm away from the tip of the head (the same is true for those shown in FIGS. 12, 15, 18, 19, and 20).
  • the amount of light emitted from the central portion is smaller than that from both end portions of the light guide portion 2. This is because the guidance toward the center side is made larger as shown in FIG. 6, but there is also light that takes an optical path as shown in FIG. 7, and this optical path is short and its intensity increases.
  • the amount of light emitted from the center is smaller than that at both ends, but the degree of the reduction is smaller than when the LED 21 is arranged on the optical axis M1 and is not tilted. The degree is small. That is, the intensity of light at the center is closer to the intensity of light at both ends.
  • FIG. 9 shows optical paths inside and outside the light scattering light guide 5 shown in FIG.
  • the scattering gradually proceeds and is emitted from the upper surface of the convex lens-shaped light scattering light guide unit 5. Refracts toward the center of the light scattering light guide 5 in the short direction. Then, it becomes scattered light and becomes an optical path K2 in which the irradiation area gradually increases. Since the other optical paths go through the same process, a linear illumination range having a predetermined width is formed at a position away from the upper surface of the light scattering light guide 5 by a predetermined distance.
  • the light emitting device 20 and the light guide 1 have an incident lens 3 that makes incident light close to parallel light, and the light close to the parallel light is totally reflected by the emission surface 6 or directly near the center.
  • the light is supplied to a certain prism unit 4 and reflected or totally reflected to be emitted.
  • incident light is incident from the lower side of the optical axis M1 of the incident lens 3 toward the oblique upper side, so that it is totally reflected by the exit surface 6 and reflected or totally reflected from the prism portion 4 near the center. The amount of light that can be increased.
  • the amount of light emitted from the central portion 1 of the light guide 1 is increased, and it is possible to suppress the generation of a strong and weak distribution in the emitted light.
  • the light reflected by the same sawtooth goes to the emission surface 6 side with a certain width. For this reason, it is possible to prevent a portion having a small amount of reflected light from occurring between the light reflected by the adjacent saw teeth, thereby causing a strong and weak stripe distribution in the emitted light.
  • the light emitting device 20 employs a configuration in which light is incident from the lower side of the optical axis M1 of the incident lens 3 toward the oblique upper side.
  • the mirror member 22 reflects light that is not directly incident on the incident lens 3 or the light guide 2 out of the light of the LED 21, and causes the reflected light to enter the incident lens 3 or the light guide 2. ing. Therefore, most of the light emitted from the LED 21 can be incident on the light guide 1.
  • the light emitting device 20 and the light guide 1 contain light scattering particles that the light scattering light guide 5 causes multiple scattering of light. Since this light scattering light guide 5 causes light scattering with large forward scattering, it is difficult to reduce the light emission efficiency.
  • the light guide 2 or the incident lens 3 is made of a transparent body or contains a light scattering light guide 5 for increasing the turbidity ⁇ . Therefore, almost no light is scattered at the stage before emission from the emission surface 6, and most of the light is scattered when the light is emitted from the light scattering light guide 5. For this reason, even when the above-described stripe distribution of the intensity of light is slightly generated when the light exits from the light exit surface 6, the light efficiency is greatly reduced by the multiple scattering of the light by the light scattering light guide 5. In addition, the stripe distribution of light intensity can be suppressed.
  • the light-scattering particles contained in the light-scattering light-guiding unit 5 have a turbidity that is a scattering parameter corresponding to the scattering coefficient of the light-scattering light-guiding unit 5 as ⁇ (unit: cm), and will be described later.
  • the maximum thickness (H2) of the light-scattering light guide 5 in the direction orthogonal to T is T (unit: cm)
  • the range is 1 ⁇ T / ⁇ ⁇ 10.
  • the value of T / ⁇ exceeds 1, the above-described stripe distribution can be further suppressed.
  • the value of T / ⁇ is less than 10, excessive multiple scattering of light is suppressed, and it becomes easy to form a linear illumination range having a predetermined width as shown in FIG.
  • the light emitting device 20 has a smaller amount of light emitted from the central portion than the both end portions of the light guide portion 2. Then, the emitted light is collected at a position away from the light scattering light guide 5 by a predetermined distance to be in a linear illumination state. For this reason, the light emitting device 20 has an image reading object installed at the predetermined distance, and the light reflected from the object is predetermined in the direction orthogonal to the longitudinal direction of the light guide unit 2 from the center of the light guide unit 2. It is suitable as a light source for a scanner that forms an image with an image sensor arranged at a distance.
  • the image sensor of the scanner moves in the longitudinal direction of the light guide unit 2 in the longitudinal direction, and the image sensor faces the center and both ends of the light guide unit 2. It is also suitable as a light source for a scanner that captures light reflected from the object.
  • both ends of the light guide 2 are light in a range with a large angle of view exceeding the range in which the image sensor moves according to the cosine fourth law, that is, light that is wasted without being imaged by the image sensor. This is because the amount of light tends to be insufficient, and when viewed from the image pickup device, both the end portions and the center portion of the light guide section 2 have substantially uniform light amounts.
  • the imaging element is linear in parallel to the light guide unit 2, the amount of incident light at both ends of the imaging element tends to decrease, but the amount of light at both ends as in the light emitting device 20. If there are many, such an evil will disappear.
  • both ends of the light guide 2 can be strongly illuminated, and if the LED 21 is shifted to the prism 4 side, the center of the light guide 2 can be strongly illuminated, but both ends It does not go to the strength of the department. Moreover, if the light which strikes the mirror surface member 22 by tilting the LED 21 is increased, the vicinity of both end portions of the light guide portion 2 can be strongly illuminated. These points are described below from another angle.
  • the vertical position (degree of shift) and / or tilt (degree of tilt) of the LED 21 shown in FIG. 5 is adjusted.
  • Increasing the amount of light emitted from the LED 21 obliquely upward from the lower side when entering the light guide unit 2 or the amount of light directed obliquely downward from the upper side is increased at both ends of the light guide unit 2.
  • More light is applied to the prism unit 4.
  • the amount of light emitted from both ends of the light guide portion 2 is much greater than the central portion, and the light at the ends becomes very strong.
  • the amount of light traveling from the upper side to the obliquely lower side or from the lower side to the obliquely upper side when entering the light guide unit 2 is reduced, and the light traveling toward the center of the light guide unit 2.
  • Increasing the amount of light increases the amount of light applied to the prism portion 4 at the center of the light guide portion 2.
  • the amount of light emitted from the central portion of the light guide 2 is increased.
  • the intensity of light at both ends is stronger than that at the center. That is, the intensity is more constant in the longitudinal direction, but the light in the center is weaker.
  • the light emitting device 20 and the light guide 1 are formed by integrating the light guide part 2 and the light scattering light guide part 5 by two-material molding. Therefore, both can be handled as a unit, and the handleability is excellent.
  • one LED 21 and one incident lens 3 are arranged at both ends of the light guide 2. Therefore, only two small amounts of LEDs 21 are used as a light source, and there are advantages such as cost reduction such as reduction in the number of members and power consumption.
  • the light emitting device 20 and the light guide 1 receive light from both ends in the longitudinal direction of the light guide 2, and the prism portion 4 has a plurality of sawtooth cross sections. The pitch P1 between the vertices of the sawtooth at the center is longer than the pitch P2 between the vertices of the sawtooth at the center.
  • FIG. 10 and FIG. 11 are schematic diagrams showing the light incident / exit status when the LED 21 of the light emitting device 20A of the first modification of the light emitting device 20 is turned on.
  • the light emitting device 20A has the same configuration as the light emitting device 20 except that the light emitting surface is the lower side in FIG. 10 perpendicular to the axis of the light guide unit 2, that is, the optical axis M1, without tilting the LED 21.
  • the reference numerals assigned to the respective constituent elements are the same as the reference numerals assigned to the respective constituent members of the light emitting member 20.
  • FIG. 10 shows an optical path emitted from both ends of the LED 21 when light is directly incident on the incident lens 3 from the LED 21.
  • FIG. 10 shows an optical path emitted from both ends of the LED 21 when light is directly incident on the incident lens 3 from the LED 21.
  • FIG. 11 shows an optical path emitted from both ends of the LED 21 when the light from the LED 21 is reflected by the mirror member 22 and is incident on the incident lens 3.
  • An optical path indicated by a fine dotted line with an arrow is an optical path of light emitted from the lower end side region of the LED 21 in FIGS. 10 and 11.
  • the optical path shown with the rough dotted line with an arrow is an optical path of the light emitted from the upper end side area
  • the light emitted from the LED 21 is divergent light, but the light emitted from the incident lens 3 is approaching parallel light.
  • the LED 21 is arranged shifted to a position below the optical axis M1 of the incident lens 3, a light emitting surface is formed when light enters the incident lens 3 having a hyperbolic shape as shown in FIG. A lot of light emitted in the vertical direction is refracted upward. Then, the light is totally reflected by the light exit surface 6 of the light guide unit 2 and redirected mainly by the prism unit 4 at the center of the light guide unit 2, passes through the light exit surface 6 in a substantially vertical direction, and further guides light scattering. The light passes through the part 5 and is emitted. In the light shown in FIG.
  • light emitted from the upper end side region of the LED 21 is mainly directed toward the central portion side of the light guide portion 2, reflected by the prism portion 4, and emitted from the central portion side of the light guide portion 2.
  • the light emitted from the side region is emitted slightly from both ends rather than the central portion of the light guide portion 2.
  • the light that is reflected by the mirror member 22 shown in FIG. 11 and is incident on the incident lens 3 is light at both ends of the light emitted from the LED 21 at a very wide angle. Since the LED 21 has light directivity in the forward direction, the amount of light at this amount end is small. In this way, the light directed upward from the wide-angle side light does not undergo total reflection at the exit surface 6 but is reflected by the mirror member 22 and passes through the incident lens 3 as it is and is directly irradiated onto the prism unit 4. The direction is changed, and the light passes through the emission surface 6 in a substantially vertical direction, and further passes through the light scattering light guide 5 and is emitted.
  • the light directed downward is reflected by the mirror member 22, passes through the incident lens 3, is reflected by the exit surface 6, travels toward the prism unit 4, and is reflected by the prism unit 4 toward the exit surface 6.
  • the light shown in FIG. 11 is emitted mainly from both end portions of the light guide unit 2.
  • FIG. 12 is a diagram showing a light emission state of the light emitting device 20A, and is a diagram showing a distribution of brightness (light quantity) of the light guide 2 with the distance from the center of the light guide 2 as the horizontal axis.
  • the light emission state of the light emitting device 20A is such that the amount of light reflected by the prism portion 4 is increased as compared with the light emitting device 20A in which the surface of the LED 21 is perpendicular to the optical axis M1 and the center of the LED 21 is disposed at both focal positions F. Further, the light intensity at both ends is slightly weakened, and the difference in light intensity between both ends and the center is reduced.
  • the light emitted from the light emitting device 20 ⁇ / b> A has a smaller amount of light emitted from the central portion than the both ends of the light guide unit 2, as in the light emitting device 20.
  • the amount of light emitted from both ends of the light guide 2 is slightly smaller than that of the light emitting device 20 as described above.
  • FIG. 13 and FIG. 14 are schematic diagrams showing the light incident / exit status when the LED 21 of the light emitting device 20B of the second modification of the light emitting device 20 is turned on.
  • the light emitting device 20B has the light emitting surface in the direction perpendicular to the axis of the light guide unit 2, that is, the optical axis M1, without tilting the LED 21, and the LED 21 is positioned above the optical axis M1 of the incident lens 3. Shift arranged. As a result of this shift, the arrangement position of the LED 21 is an intermediate position between the optical axis M 1 and the emission surface 6.
  • the pitch P3 between the vertices of the concave portion 14A in the central portion of the light guide portion 2A is larger than the pitch P4 between the vertices of the concave portions 13A at both ends of the light guide portion 2A.
  • the prism angles in the range of the pitch P3 between the vertices are each 30 °, and the prism angles in the range of the pitch P4 between the vertices are each 40 °. Except for these points, the configuration is the same as that of the light emitting device 20, and therefore, the reference numerals assigned to the respective constituent elements are the same as the reference numerals assigned to the respective constituent members of the light emitting member 20.
  • FIG. 13 shows a light path emitted from both ends of the LED 21 when light is directly incident on the incident lens 3 from the LED 21.
  • FIG. 14 shows an optical path emitted from both ends of the LED 21 when the light from the LED 21 is reflected by the mirror member 22 and is incident on the incident lens 3.
  • An optical path indicated by a fine dotted line with an arrow is an optical path of light emitted from the lower end side region of the LED 21 in FIGS. 13 and 14.
  • the optical path shown with the rough dotted line with an arrow is an optical path of the light emitted from the upper end side area
  • the light emitted from the LED 21 is divergent light, but the light emitted from the incident lens 3 is approaching parallel light. Further, since the LED 21 is arranged shifted to a position above the optical axis M1 of the incident lens 3, as shown in FIG. 13, when the light is incident on the incident lens 3 having a hyperbolic shape, the LED 21 is placed on the light emitting surface. On the other hand, a lot of light emitted in the vertical direction is refracted downward. Then, the direction is changed by the prism portions 4 at the center portion and both end portions of the light guide portion 2, passes through the emission surface 6 in a substantially vertical direction, and further passes through the light scattering light guide portion 5 to be emitted. In the light shown in FIG.
  • the light that is reflected by the mirror member 22 shown in FIG. 14 and is incident on the incident lens 3 is light emitted from the LED 21 to the very wide angle side.
  • the light directed downward is reflected by the prism portion 4 ⁇ / b> A through total reflection at the exit surface 6 and passes through the exit surface 6.
  • the light directed upward is reflected by the mirror member 22 without undergoing total reflection at the exit surface 6, passes through the incident lens 3 as it is, and is directly irradiated to the prism portion 4 ⁇ / b> A. Pass vertically. Any light is further emitted through the light scattering light guide 5.
  • the light shown in FIG. 14 is emitted mainly from both ends A of the light guide 2. Note that, by making the pitch P3 larger than the pitch P4, the shape of the both end portions of the light guide portion 2A that is mainly emitted does not become complicated, so that the dimensional accuracy at the time of molding or the like is increased.
  • FIG. 15 is a diagram showing a light emission state of the light emitting device 20B, and is a diagram showing a distribution of brightness (light quantity) of the light guide 2 with the distance from the center of the light guide 2 as the horizontal axis.
  • the light emitting state of the light emitting device 20B is substantially the same as the light emitting state of the light emitting devices 20 and 20A in that both end portions are bright and the central portion is dark.
  • the amount of light emitted from both ends of the light guide 2A is larger than that of the light emitting devices 20 and 20A.
  • a large amount of light emitted from both ends is emitted from a position slightly away from the LED 21 as compared with the light emitting devices 20 and 20A.
  • FIG. 16 is a diagram showing a light emitting state of a light emitting device 20C (not shown) of the third modification of the light emitting device 20, and the brightness of the light guide unit 2 is plotted with the distance from the center of the light guide unit 2 as the horizontal axis. It is a figure which shows distribution of (light quantity).
  • the light emitting device 20C has a light emitting surface in a direction perpendicular to the axis of the light guide unit 2, that is, the optical axis M1, and the LED 21 is shifted to a position above the optical axis M1 of the incident lens 3. .
  • the arrangement position of the LED 21 is an intermediate position between the optical axis M 1 and the emission surface 6.
  • the LED 21 is inclined 45 ° toward the prism portion 4A (downward). Furthermore, the light-emitting device 20C uses the light guide portion 2A having the prism portion 4A as in the light-emitting device 20B.
  • the configuration of the light emitting device 20C is the same as that of the light emitting device 20 except for these points.
  • the light emitting state of the light emitting device 20C is substantially the same as the light emitting state of the light emitting devices 20, 20A, 20B in that both ends are dark and the center is dark.
  • the amount of light emitted from both ends of the light guide 2A is equivalent to that of the light emitting device 20B. A lot of light emitted from both ends is emitted from substantially the same position as the light emitting device 20B.
  • FIG. 17 and FIG. 18 are schematic diagrams showing the state of light entering and exiting when the LED 21 of the light emitting device 20D of the comparative example is turned on.
  • the light emitting device 20D has a light emitting surface in a direction perpendicular to the axis of the light guide unit 2, that is, the optical axis M1, without tilting the LED 21, and the center of the LED 21 is disposed at the both focal positions F. Except for these points, the configuration is the same as that of the light emitting device 20, and therefore, the reference numerals assigned to the respective constituent elements are the same as the reference numerals assigned to the respective constituent members of the light emitting member 20.
  • FIG. 17 shows a light path emitted from both ends of the LED 21 when light is directly incident on the incident lens 3 from the LED 21.
  • FIG. 18 shows an optical path emitted from both ends of the LED 21 when the light from the LED 21 is reflected by the mirror surface member 22 and is incident on the incident lens 3.
  • An optical path indicated by a fine dotted line with an arrow is an optical path of light emitted from the lower end side region of the LED 21 in FIGS. 17 and 18.
  • the optical path shown with the rough dotted line with an arrow is an optical path of the light emitted from the upper end side area
  • the light emitted from the LED 21 is divergent light, but the light emitted from the incident lens 3 is approaching parallel light. Since the center of the LED 21 is disposed at the focal position of the incident lens 3, that is, both focal positions F, the lower end side of the LED 21 when light enters the incident lens 3 having a hyperbolic shape as shown in FIG. A lot of light emitted from the region is refracted upward. Then, the light is totally reflected by the light exit surface 6 of the light guide 2 and is changed in direction mainly by the prism portion 4 at the center of the light guide 2, passes through the light exit surface 6 in a substantially vertical direction, and further the light scattering light guide 5. It passes through and is emitted.
  • the light emitted from the upper end side region of the LED 21 is refracted downward. Then, the light is redirected to a slightly acute angle by the prisms 4 at both ends of the light guide 2, passes through the exit surface 6, and further passes through the light scattering light guide 5 and exits. Further, the light emitted from the LED 21 at a relatively wide angle does not irradiate the prism unit 4 and travels straight through the light guide unit 2 in the longitudinal direction. A part of the light traveling straight is reflected by the mirror member 22 on the opposite side, enters the light guide unit 2 again, and finally passes through the light scattering light guide unit 5 and is emitted. In the light shown in FIG.
  • the light that is reflected by the mirror member 22 shown in FIG. 18 and enters the incident lens 3 is light that is emitted from the LED 21 to the very wide angle side.
  • the light shown in FIG. 18 is emitted mainly from both end portions of the light guide unit 2.
  • FIG. 19 is a diagram showing the light emission state of the light emitting device 20D, and is a diagram showing the distribution of the brightness (light quantity) of the light guide 2 with the distance from the center of the light guide 2 as the horizontal axis.
  • the light emitting state of the light emitting device 20D is substantially the same as the light emitting state of the light emitting devices 20, 20A, 20B, and 20C in that the amount of light emitted from the central portion is smaller than both ends of the light guide unit 2. .
  • the difference between the amount of light emitted from both ends of the light guide 2 and the amount of light emitted from the center of the light guide 2 is larger than that of the light emitting devices 20 and 20A, and the light emitting device 20B. , Less than that of 20C.
  • a large amount of fluctuations in the light emission amount in the central portion occur in small increments.
  • FIG. 20 shows the light emission state of the light emitting device in which the arrangement of the LEDs 21 is the same as that of the light emitting device 20D and the incident lens 3 is omitted.
  • the incident lens 3 may be eliminated.
  • one or both of shift and tilt may be employed.
  • optical element (light guide 1) and the light emitting devices 20, 20A, 20B, and 20C in the embodiment of the present invention have been described above, but various modifications can be made without departing from the gist of the present invention.
  • the light-emitting devices 20, 20A, 20B, and 20C include rod-shaped light guides 2 and 2A, LEDs 21 that make light incident on the light guides 2 and 2A, and light guides 2 and 2A.
  • a light emitting device that includes prism portions 4 and 4A that change the direction of light incident from the end in the longitudinal direction, and that emits the light whose direction has been changed from the emission surface 6 disposed so as to face the prism portions 4 and 4A.
  • light beams emitted from the LED 21 toward the light guide sections 2 and 2A are made parallel light beams at the longitudinal ends of the light guide sections 2 and 2A.
  • the incident lens 3 is formed, and the LED 21 shifts light from the central axis of the light guides 2 and 2A toward the side closer to the prisms 4 and 4A or away from the prisms 4 and 4A, thereby approaching the parallel light.
  • the light exit surface of the light guides 2 and 2A Or it is configured to face the prism unit 4, 4A.
  • the prism parts 4 and 4A are arrange
  • the prism portions 4 and 4 ⁇ / b> A may not be parallel to the emission surface 6, but may be inclined so as to approach the emission surface 6 as the distance from the LED 21 increases.
  • a member that reflects light such as a mirror or a white surface, may be used instead of the prism portions 4 and 4A.
  • the prism portions 4 and 4A and / or the emission surface 6 can be formed in a curved surface shape or the like instead of a planar shape.
  • the emission surface 6 can have a cylindrical side surface shape similar to the upper surface of the light scattering light guide 5.
  • the light guides 2 and 2A are made of PMMA, but other acrylic ester or methacrylic ester polymer, which is an acrylic resin that is a highly transparent amorphous synthetic resin, Other light-transmitting resins such as polystyrene and polycarbonate, and those made of glass can be used.
  • the incident lens 3 used as a convex lens is used as a parallel light formation body
  • LED21 when LED21 is arrange
  • the concave reflecting mirror may be a parallel light forming body.
  • the light emitting devices 20, 20 ⁇ / b> A, 20 ⁇ / b> B, and 20 ⁇ / b> C reflect the light that is not directly incident from the LED 21 to the incident lens 3 around the LED 21 and causes the mirror member 22 to enter the incident lens 3. It has.
  • the mirror member 22 is not an essential component and can be omitted.
  • the light emitting devices 20, 20 ⁇ / b> A, 20 ⁇ / b> B, and 20 ⁇ / b> C preferably include a mirror surface member 22.
  • the mirror member 22 needs to have a cup shape in which the longitudinal section in FIG. 5 draws a parabolic curve.
  • other shapes such as a spherical shape may be used.
  • the reflecting member may have a surface that reflects light such as a white surface instead of a mirror surface like the mirror member 22.
  • the incident lens 3 as a parallel light forming body used in the light emitting devices 20, 20A, 20B, and 20C according to the embodiment of the present invention is an incident lens 3 whose side facing the LED 21 is swollen.
  • the LEDs 21 used in the light emitting devices 20 and 20A are shifted from the optical axis M1 of the incident lens 3 to the side closer to the prism portions 4 and 4A.
  • the LED 21 may be shifted from the prism parts 4 and 4A around the optical axis M1 of the incident lens 3 as a center.
  • the incident lens 3 is not an essential component and can be omitted.
  • the parallel light forming body replacing the incident lens 3 is, for example, a concave mirror as described above.
  • the concave mirror can reflect the diverging light emitted from the LED 21 and make the reflected light close to parallel light. Further, even when a convex lens is used as the parallel light forming body, the convex lens does not need to have a hyperbolic cross section like the incident lens 3.
  • LED21 used for light-emitting device 20,20A, 20B, 20C which concerns on embodiment of this invention seems that the surface of the emitted light inclines with respect to the optical axis M1 which is a central axis of the light guide parts 2 and 2A. Is arranged. However, since the arrangement of the LEDs 21 is not an essential component, it is not necessarily adopted. Moreover, even if it is a case where it employ
  • the optical element (light guide 1) and the light emitting devices 20, 20A, 20B, and 20C according to the embodiment of the present invention are provided with the light guide unit 2 and 2A on the light exit surface 6 side that serve as light exit surfaces.
  • a light scattering light guide 5 containing light scattering particles for multiple scattering of emitted light is not an essential component and can be omitted.
  • the light scattering particles are spherical and translucent silicone particles having a particle diameter of 2 ⁇ m to 9 ⁇ m.
  • various particles can be used regardless of the material, shape, particle diameter, and the like as long as the light in the light transmissive member 1 is subjected to multiple scattering.
  • spherical and translucent silicone particles having a particle diameter of 2 ⁇ m to 9 ⁇ m, more preferably 5 ⁇ m to 9 ⁇ m, should be used. Is preferred.
  • the light scattering particles can be omitted because they are not essential components. Further, the light scattering particles can be included not only in the light scattering light guide 5 but also in the light guides 2 and 2A, and not included in the light scattering light guide 5 but only in the light guides 2 and 2A. Can be included.
  • the light scattering particles contained in the light guides 2 and 2A have turbidity, which is a scattering parameter corresponding to the scattering coefficient of the light guides 2 and 2A, as ⁇ , and are in the direction of the central axis of the light guides 2 and 2A.
  • L a scattering parameter corresponding to the scattering coefficient of the light guides 2 and 2A, as ⁇
  • ⁇ a scattering parameter corresponding to the scattering coefficient of the light guides 2 and 2A
  • the light scattering particles contained in the light guides 2 and 2A have turbidity, which is a scattering parameter corresponding to the scattering coefficient of the light guides 2 and 2A, as ⁇ , and are in the direction of the central axis of the light guides 2 and 2A.
  • the light scattering particles contained in the light scattering light guide 5 have a turbidity that is a scattering parameter corresponding to the scattering coefficient of the light scattering light guide 5, and ⁇ is a light scattering guide in a direction orthogonal to the exit surface 6.
  • T the maximum thickness of the optical part 5
  • the range is 1 ⁇ T / ⁇ ⁇ 10.
  • the mean free path of the light incident on the light guides 2 and 2A or the light scattering light guide 5 is t
  • the mean free path is preferably in the range of 1/4 t to 1/2 t.
  • one LED 21 and one incident lens 3 are disposed at both ends of the light guides 2 and 2A, respectively.
  • the amount of light emitted from the center portion is smaller than that from both end portions.
  • the amount of emitted light at the center is greatly increased compared to the case where the LEDs 21 are simply arranged.
  • the light amount distribution having a gentle concave shape by increasing the light amount in the central portion is not essential and need not be adopted.
  • such a light quantity distribution is preferable for a scanner.
  • two or more LEDs 21 and / or incident lenses 3 may be arranged at both ends or one end of the light guides 2 and 2A.
  • An optical element (light guide 1) includes rod-shaped light guides 2 and 2A and a prism that changes the direction of light incident from the ends in the longitudinal direction of the light guides 2 and 2A.
  • the optical element that has the portions 4 and 4A and emits the light whose direction is changed from the emission surface 6 disposed so as to face the prism portions 4 and 4A
  • the end portions in the longitudinal direction of the light guide portions 2 and 2A Is formed with an incident lens 3 that brings light emitted from the LED 21 toward the light guides 2 and 2A close to parallel light.
  • the prism parts 4 and 4A are arranged so as to be parallel to the emission surface 6, this is not necessary.
  • the light guide parts 2 and 2A are made into a rod shape, they can be formed into a flat and rectangular parallelepiped shape instead of a rod shape, or a bent rod shape even in the case of a rod shape.
  • the shape of the incident lens 3 is devised and incident. This can be achieved by refracting light toward the exit surface 6 or the prism portions 4 and 4A.
  • the light scattering light guide 5 used in the optical element (light guide 1) and the light emitting devices 20, 20A, 20B, and 20C according to the embodiment of the present invention has a rod shape, and the light guides 2 and 2A
  • the surface opposite to the facing surface has a convex curved shape in which the central portion in the short direction swells.
  • the light-scattering light guide 5 may have another shape such as a plate shape that is long in the light emission direction instead of a rod shape.
  • the light scattering light guide 5 has a surface opposite to the surface facing the light guides 2 and 2A having another shape such as a concave curved surface shape or a planar shape in which the central portion in the short direction is recessed. Also good.
  • the concave shape is adopted, the emitted light becomes divergent light, and the light emitting devices 20, 20A, 20B, and 20C are suitable for lighting devices that illuminate a wide angle.
  • the light guides 2 and 2A and the light scattering light guide 5 used in the optical element (light guide 1) and the light emitting devices 20, 20A, 20B, and 20C according to the embodiment of the present invention are integrated. Yes.
  • the light guides 2 and 2A and the light scattering light guide 5 may be separate members. In that case, the illumination pattern can be changed in accordance with the use of the illumination devices 20, 20A, 20B, and 20C.
  • the light incident on the optical element (light guide 1) and the light guides 2 and 2A used in the light emitting devices 20, 20A, 20B, and 20C according to the embodiment of the present invention is subjected to multiple scattering as described above. It is good also as containing the light-scattering particle to make.
  • the incident lens 3 may also contain light scattering particles.
  • the light guide parts 2 and 2A and the light-scattering light guide part 5 are made into the integral molding of the same member instead of 2 material shaping
  • it may become difficult to produce strong and weak stripe distribution in emitted light.
  • one LED 21 (light source) and one incident lens 3 are arranged at both ends of the light guide unit 2 used in the optical element (light guide 1) and the light emitting devices 20 and 20A according to the embodiment of the present invention.
  • the pitches (P1, P2) between the vertices of the saw teeth are long.
  • the LED 21 (light source) and / or the incident lens 3 may be disposed not at both ends of the light guide 2 but at one end.
  • two or more LEDs 21 (light sources) and / or incident lenses 3 may be arranged at both ends or one end of the light guide 2.
  • the pitch between the vertices of the saw blades can be set as appropriate depending on the purpose and application. For example, the pitches between the vertices of all the saw blades are made equal to each other, or the pitch between the vertices of the respective saw blades is larger at the center portion than the both end portions of the light guide portion 2A as in the light guide portion 1A and the light emitting devices 20B and 20C.
  • P3, P4) can be set longer, and the pitch between the vertices of the sawtooth can be set gradually shorter toward one end of the light guides 2 and 2A.
  • the LED 21 used in the light emitting devices 20 and 20A according to the embodiment of the present invention is shifted and arranged at an intermediate position between the central axis (optical axis M1) of the light guides 2 and 2A and the prism unit 4.
  • LED21 used for the light-emitting device 20 is with respect to the central axis (optical axis M1) of the light guide parts 2 and 2A so that light may be irradiated with respect to the incident lens 3 toward the diagonally upper side from the lower side of FIG. And tilted by 45 ° (tilt amount).
  • LED21 used for light-emitting device 20B, 20C which concerns on embodiment of this invention is arrange
  • the LEDs 21 used in the light emitting devices 20B and 20C are tilted at an angle of 45 ° (tilt amount) with respect to the central axis (optical axis M1) of the light guide portions 2 and 2A toward the prism portion 4A. These shift positions and tilt amounts can be changed as appropriate.
  • the shift position is a prism extending from the central axis (optical axis M1) of the light guides 2 and 2A and extending from the central axis (optical axis M1) of the light guides 2 and 2A. It can be appropriately set on a line orthogonal to the portions 4 and 4A. Further, the tilt amount is 5 ° to 85 so that the light emitting surface of the LED 21 is directed to the central axis (optical axis M1) of the light guides 2 and 2A from a state where the light is not tilted at all, such as the light emitting devices 20A and 20B. It can be set as appropriate within the range of °.

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Abstract

L'invention concerne un dispositif électroluminescent et un élément électroluminescent qui permettent de diminuer les difficultés de fabrication, tout en améliorant l'efficacité d'éclairage et en commandant la répartition de l'intensité produite par la lumière émise. Un dispositif électroluminescent (20) comprend un guide de lumière en forme de tige (2), une LED (21) qui émet de la lumière vers le guide de lumière (2), et un prisme (4) qui change la direction de la lumière émise depuis l'extrémité longitudinale du guide de lumière (2) et qui émet une lumière redirigée depuis une surface de sortie de lumière (6) disposée à l'opposé du prisme (4). Le dispositif électroluminescent (20) est conçu de telle sorte qu'une lentille d'entrée (3) est formée à l'extrémité longitudinale du guide de lumière (2), en tant que corps de mise en forme de lumière parallèle pour que la lumière sortant de la LED (21) vers le guide de lumière (2) soit une lumière presque parallèle ; la LED (21) est décalée par rapport à l'axe central du guide de lumière (2) vers le côté le plus proche du prisme (4) ou vers le côté éloigné du prisme (4) ; et ladite lumière presque parallèle est ainsi dirigée vers la surface de sortie (6) du guide de lumière (2) ou vers le prisme (4).
PCT/JP2010/000948 2009-02-24 2010-02-16 Dispositif électroluminescent et élément électroluminescent WO2010098036A1 (fr)

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JP2009041168A JP5336880B2 (ja) 2009-02-24 2009-02-24 発光装置

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JP2013201746A (ja) * 2012-02-24 2013-10-03 Ricoh Co Ltd 光照射光学系、画像読取装置及び画像形成装置
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